In a study examining how high-fat foods impacted smell, neuroscientists from Florida State University found that high-fat diet is linked to major structural and functional changes in the olfactory system, which gives us our sense of smell.

In lab experiments, mice were given a high-fat daily diet while also being taught to associate between a particular odour and a reward (water). Mice that were fed the high-fat diets were slower to learn the association than the control population.

When researchers introduced a new odour to monitor their adjustment, the mice with the high-fat diets could not rapidly adapt, demonstrating reduced smell capabilities.

"Moreover, when high-fat-reared mice were placed on a diet of control food during which they returned to normal body weight and blood chemistry, mice still had reduced olfactory capacities," Debra Ann Fadool, a biological science professor at Florida State University, explained.

Mice exposed to high-fat diets only had 50 percent of the neurons that could operate to encode odour signals. It is the first time researchers had been able to demonstrate a solid link between a bad diet and a loss of smell.

"This opens up a lot of possibilities for obesity research," said post-doctoral researcher Nicolas Thiebaud.